vii THREE STROKES OF A DAGGER 97
segment, and this in proportion as the ganglia are more
widely separated and distant from each other. If, on
the contrary, they are soldered together, injury to the
common centre causes paralysis of all the segments
where its ramifications spread. This is the case
with Buprestids and Weevils, which the Cerceris
paralyses by a single sting, directed at the common
mass of the nerve centres in the thorax. But open
a cricket, and what do we find to animate the three
pairs of feet ? We find what the Sphex knew long
before the anatomist, three nerve centres far apart
Thence the fine logic of the three stabs. Proud
science! humble thyself.
Crickets sacrificed by Sphex flavipennis are no more
dead, in spite of all appearances, than are Weevils
struck by a Cerceris. The flexibility of the integuments
displays the slightest internal movement, and thus makes
useless the artificial means used by me to show some
remains of life in the Cleonus of Cerceris tuberculata.
If one closely observes a cricket stretched on its back a
week or even a fortnight or more after the murder, one
sees the abdomen heave strongly at long intervals.
Very often one can notice a quiver of the palpi and
marked movements in the antennae and the bands of
the abdomen, which separate and then come suddenly
together, By putting such crickets into glass tubes
I have kept them perfectly fresh for six weeks.
Consequently, the Sphex larvae, which live less than a
fortnight before enclosing themselves in their cocoons,
are sure of fresh food as long as they care to feast
The chase is over; the three or four crickets
needed to store a cell are heaped methodically on
their backs, their heads at the far end, their feet
H